<?php

    /**
     * PHPExcel_Worksheet_ColumnCellIterator
     * Copyright (c) 2006 - 2015 PHPExcel
     * This library is free software; you can redistribute it and/or
     * modify it under the terms of the GNU Lesser General Public
     * License as published by the Free Software Foundation; either
     * version 2.1 of the License, or (at your option) any later version.
     * This library is distributed in the hope that it will be useful,
     * but WITHOUT ANY WARRANTY; without even the implied warranty of
     * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
     * Lesser General Public License for more details.
     * You should have received a copy of the GNU Lesser General Public
     * License along with this library; if not, write to the Free Software
     * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
     * @category   PHPExcel
     * @package    PHPExcel_Worksheet
     * @copyright  Copyright (c) 2006 - 2015 PHPExcel (http://www.codeplex.com/PHPExcel)
     * @license    http://www.gnu.org/licenses/old-licenses/lgpl-2.1.txt    LGPL
     * @version    ##VERSION##, ##DATE##
     */
    class PHPExcel_Worksheet_ColumnCellIterator extends PHPExcel_Worksheet_CellIterator implements Iterator {
        /**
         * Column index
         * @var string
         */
        protected $columnIndex;
        /**
         * Start position
         * @var int
         */
        protected $startRow = 1;
        /**
         * End position
         * @var int
         */
        protected $endRow = 1;

        /**
         * Create a new row iterator
         * @param    PHPExcel_Worksheet $subject     The worksheet to iterate over
         * @param   string              $columnIndex The column that we want to iterate
         * @param    integer            $startRow    The row number at which to start iterating
         * @param    integer            $endRow      Optionally, the row number at which to stop iterating
         */
        public function __construct(PHPExcel_Worksheet $subject = null, $columnIndex = 'A', $startRow = 1, $endRow = null) {
            // Set subject
            $this->subject     = $subject;
            $this->columnIndex = PHPExcel_Cell::columnIndexFromString($columnIndex) - 1;
            $this->resetEnd($endRow);
            $this->resetStart($startRow);
        }

        /**
         * (Re)Set the end row
         * @param integer $endRow The row number at which to stop iterating
         * @return PHPExcel_Worksheet_ColumnCellIterator
         * @throws PHPExcel_Exception
         */
        public function resetEnd($endRow = null) {
            $this->endRow = ($endRow) ? $endRow : $this->subject->getHighestRow();
            $this->adjustForExistingOnlyRange();
            return $this;
        }

        /**
         * Validate start/end values for "IterateOnlyExistingCells" mode, and adjust if necessary
         * @throws PHPExcel_Exception
         */
        protected function adjustForExistingOnlyRange() {
            if ($this->onlyExistingCells) {
                while ((!$this->subject->cellExistsByColumnAndRow($this->columnIndex, $this->startRow)) && ($this->startRow <= $this->endRow)) {
                    ++$this->startRow;
                }
                if ($this->startRow > $this->endRow) {
                    throw new PHPExcel_Exception('No cells exist within the specified range');
                }
                while ((!$this->subject->cellExistsByColumnAndRow($this->columnIndex, $this->endRow)) && ($this->endRow >= $this->startRow)) {
                    --$this->endRow;
                }
                if ($this->endRow < $this->startRow) {
                    throw new PHPExcel_Exception('No cells exist within the specified range');
                }
            }
        }

        /**
         * (Re)Set the start row and the current row pointer
         * @param integer $startRow The row number at which to start iterating
         * @return PHPExcel_Worksheet_ColumnCellIterator
         * @throws PHPExcel_Exception
         */
        public function resetStart($startRow = 1) {
            $this->startRow = $startRow;
            $this->adjustForExistingOnlyRange();
            $this->seek($startRow);
            return $this;
        }

        /**
         * Set the row pointer to the selected row
         * @param integer $row The row number to set the current pointer at
         * @return PHPExcel_Worksheet_ColumnCellIterator
         * @throws PHPExcel_Exception
         */
        public function seek($row = 1) {
            if (($row < $this->startRow) || ($row > $this->endRow)) {
                throw new PHPExcel_Exception("Row $row is out of range ({$this->startRow} - {$this->endRow})");
            } elseif ($this->onlyExistingCells && !($this->subject->cellExistsByColumnAndRow($this->columnIndex, $row))) {
                throw new PHPExcel_Exception('In "IterateOnlyExistingCells" mode and Cell does not exist');
            }
            $this->position = $row;
            return $this;
        }

        /**
         * Destructor
         */
        public function __destruct() {
            unset($this->subject);
        }

        /**
         * Rewind the iterator to the starting row
         */
        public function rewind() {
            $this->position = $this->startRow;
        }

        /**
         * Return the current cell in this worksheet column
         * @return PHPExcel_Worksheet_Row
         */
        public function current() {
            return $this->subject->getCellByColumnAndRow($this->columnIndex, $this->position);
        }

        /**
         * Return the current iterator key
         * @return int
         */
        public function key() {
            return $this->position;
        }

        /**
         * Set the iterator to its next value
         */
        public function next() {
            do {
                ++$this->position;
            } while (($this->onlyExistingCells) && (!$this->subject->cellExistsByColumnAndRow($this->columnIndex, $this->position)) && ($this->position <= $this->endRow));
        }

        /**
         * Set the iterator to its previous value
         */
        public function prev() {
            if ($this->position <= $this->startRow) {
                throw new PHPExcel_Exception("Row is already at the beginning of range ({$this->startRow} - {$this->endRow})");
            }
            do {
                --$this->position;
            } while (($this->onlyExistingCells) && (!$this->subject->cellExistsByColumnAndRow($this->columnIndex, $this->position)) && ($this->position >= $this->startRow));
        }

        /**
         * Indicate if more rows exist in the worksheet range of rows that we're iterating
         * @return boolean
         */
        public function valid() {
            return $this->position <= $this->endRow;
        }
    }
